What were the circumstances that led to the creation of 'One Day' cricket in 1971?

The first one-dayer at international level was played at the MCG on Tuesday 5th January 1971. The third test Australia v England was been abandoned on the 3rd day due to rain (the first two had also been a wash out). The two teams played a one-off ODI on what would've been the 5th day of the abandoned test. Each team bowled 40 eight-ball overs. Australia won by 5 wickets.
https://www.espncricinfo.com/series/england-marylebone-cricket-club-tour-of-australia-1970-71-61725/australia-vs-england-only-odi-64148/full-scorecard

But even before the squads assembled for the New Year Test at the MCG it had started raining and temperatures lingered around 50°F. The scheduled first two days were called off well in advance, and a suggestion they could start on a Sunday to make up for lost time was rejected by both boards with spluttering references to creating dangerous precedents. Heavy rain over the weekend meant the match was abandoned on the third day ... the Melbourne authorities facing losses of up to £80,000 ...

As a short-term measure to give the public something to watch, it was also agreed to play a match "on Gillette Cup lines" on what would have been the fifth day of the Test. There was still a reluctance from the establishment to completely endorse the game, and the sides were named as an England XI and Australian XI ... There were doubters in the media about the match and some predicted it would not prove popular, especially as it was on a Tuesday. The day before, the MCG had instructed caterers to prepare for a crowd of around 20,000; as it was, 46,006 turned out.

https://www.espncricinfo.com/story/rewind-to-1971-the-birth-of-the-one-day-international-464234